Adaptable reciprocating slat conveyor

ABSTRACT

A multi-operating-mode reciprocating slat conveyor having a plurality of operating modes (each operating mode having a predetermined number of steps) and means for switching between operating modes responsive to at least one operating mode changing event.

The present application is an application claiming the benefit under 35USC Section 119(e) of U.S. Provisional Patent Application Ser. No.61/236,513, filed Aug. 24, 2000. The present application is based on andclaims priority from this application, the disclosure of which is herebyexpressly incorporated herein by reference in its entirety.

BACKGROUND OF INVENTION

The present invention is directed to a reciprocating slat conveyor and,more specifically, to an adaptable or multi-mode reciprocating slatconveyor.

Reciprocating slat-type conveyors (also referred to as “conveyorsystems,” “live floor conveyors,” “reciprocating slat conveyors,” or“conveyors”) generally include a plurality of elongated slats (alsoreferred to as “conveyor slats,” “floor slats,” or “deck slats”). Theconveyors are generally used in the load-holding compartment of loadtransport vehicles (e.g. a mobile cargo trailer, bed of a truck (truckbed), rear portion of a semi-trailer, or container portion of avan-truck). The load-holding compartment has a front end toward thefront of the compartment (e.g. in a truck the front end would be the endtoward the driver compartment) and a back or rear end (e.g. in a truckthe back end would be the end into which the load would be inserted andfrom which the load would be removed). The slats are arrangedside-by-side to form the floor of the load-holding compartment so thatthey extend longitudinally to the framework of the load-holdingcompartment. A “load” may be, for example, silage, grain, fertilizer,soil, sand, shredded documents, chipped wood, sawdust, garbage, or anyparticulate matter.

The slats are generally grouped in groups of two or more slats (groupsof n slats). Groups may also include one or more stationary slats. Forthe purpose of description, respective slats from each group will bereferred to as a “set.” The slats in each set move simultaneously in onedirection (the “load-conveying direction” or “conveying direction”) andthen return (in the “load-retracting direction” or “retractingdirection”) to the beginning position. The slats' back and forthmovement results in a step-wise advance of the load positioned on thefloor followed by a retraction of the slats without moving the load. Ifa truck were being loaded, the load-conveying direction would be towardthe front end of the load-holding compartment and the load-retractingdirection would be toward the rear end of the load-holding compartment.If a truck were being unloaded (a more typical use), the load-conveyingdirection would be toward the rear end of the load-holding compartmentand the load-retracting direction would be toward the front end of theload-holding compartment.

Reciprocating slat conveyors can be categorized based on the number of“steps” each group of slats performs in the load-retracting direction(e.g. if the slats in a three-slat group each retract individually, itis a three-step system, but if only two slats of a three-slat groupretract, and the third is held in place, it is a two-step system.Another categorization is based on whether the loading/unloading motionis continuous (conveying motion by majority of slats doesn't stop movingthe load while a minority retract) or non-continuous (conveying motionstops while each slat set retracts).

U.S. Pat. No. 4,856,645 to Hallstrom (which is hereinincorporated-by-reference in its entirety) describes a two-stepnon-continuous reciprocating slat type conveyor that includes twolongitudinally extending, laterally spaced apart, first and second setsof alternating slats arranged for longitudinal sliding movement on theplane of the bed. Interposed between adjacent reciprocating slats is athird fixed slat mounted immovably to the framework. A pair ofdouble-acting hydraulic cylinders are provided to move the sets ofreciprocative slats longitudinally, the first set of reciprocative slatsbeing connected to the first cylinder and the second set being connectedto the second cylinder, so that adjacent reciprocative slats are able tomove independently of each other while every other reciprocative slatoperates in unison off the same drive, whereby both sets ofreciprocative slats can be moved in the conveying directionsimultaneously, and each set of reciprocative slats can be moved in theopposite, retracting direction independently of the other.

U.S. Pat. No. 4,962,848 to Foster (which is hereinincorporated-by-reference in its entirety) describes a two-stepnon-continuous reciprocating floor conveyor that includes groups havingtwo movable floor members and a third fixed, immovable floor member. Theprimary difference between the invention described in the Foster patentand the invention described in U.S. Pat. No. 4,856,645 to Hallstrom isin the location of the moving floor members in relation to the fixed,immovable floor member.

U.S. Pat. No. 3,534,875 to Hallstrom (which is hereinincorporated-by-reference in its entirety) describes a three-stepcontinuous reciprocating slat-type conveyor. In the Hallstrom '875patent, groups of at least three elongated slats are arranged side byside to form a conveyor-type truck bed. The slats of each group areconnected to a drive mechanism in such a manner that there are always agreater number of slats of each group moving simultaneously in theconveying direction while the remaining slat or slats of the group movein the opposite, retracting direction. Drive means are included that areoperable to move more than half of the number of slat members of eachgroup simultaneously in a conveying direction and to move the remainderof the slats of each group in the opposite direction at a higher rate ofspeed. For example, the Hallstrom '875 patent describes an embodiment inwhich there are two sets of slats conveying and one set of slatsretracting.

U.S. Pat. No. 4,143,760 to Hallstrom (which is hereinincorporated-by-reference in its entirety) describes a three-stepnon-continuous reciprocating slat-type conveyor in which the slats areconnected to a fluid pressure drive mechanism that is operable to moveall of the slats of each group from a start position simultaneously in aload-conveying direction and then to move the slats of each groupsequentially (in sets of respective slats) in the opposite, retractingdirection from the advanced position back to the start position. Theslats of each group are interengaged releasably in the conveyingdirection to ensure simultaneous movement.

U.S. Pat. No. 4,793,468 to Hamilton (which is hereinincorporated-by-reference in its entirety) describes an apparatus, and arelated method, for controlling a four-step continuously moving floorhaving multiple sliding slats, to produce a practically uniformload-moving force on a load carried on the apparatus. The slats arereciprocated back and forth by hydraulic cylinders, each of whichcontrols a set of slats that are moved together. At any given time, amajority of slats is moving together in the desired direction, andcarrying a load in this direction at a nearly uniform velocity. Theremainder of the slats is moved in a reverse direction, but at a speedthat is a multiple of the forward speed of the majority of the slats.Each set of slats is moved through a forward stroke at a relatively lowspeed; then through a backward stroke at a higher speed.

U.S. Pat. No. 4,580,678 to Foster (which is hereinincorporated-by-reference in its entirety) describes a six-stepcontinuously moving conveyor that uses two separate sources of hydraulicpressure, one for advancing the floor slat members and another forretracting the floor slat members. A majority of the floor is alwaysmoving in the conveying direction while a minority of the floor is beingretracted at a greater rate of speed.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a reciprocating slat conveyor and,more specifically, to an adaptable or multi-mode reciprocating slatconveyor.

A multi-operating-mode reciprocating slat conveyor includes a pluralityof slats arranged in groups (the slats being movable in a load-conveyingdirection and a load-retracting direction) and one slat of each group ispreferably attached to at least one power source (or sub-power unit).The multi-operating-mode reciprocating slat conveyor has a plurality ofoperating modes (at least one of which is an initial operating mode),each operating mode having a predetermined number of steps for moving apredetermined number of slats in each group of slats in theload-retracting direction. At least one of the plurality of operatingmodes is an initial operating mode. The multi-operating-modereciprocating slat conveyor has a means for switching to a new operatingmode, the means for switching being responsive to at least one operatingmode changing event.

A multi-operating-mode reciprocating slat conveyor for loading andunloading at least one load from a load-holding compartment includes aplurality of slats arranged in groups of n slats (n being a numbergreater than or equal to three (3)) and n power sources. The slats aremovable in a load-conveying direction and a load-retracting direction.One slat of each group attached to each power source (or sub-powerunit). The multi-operating-mode reciprocating slat conveyor has aplurality of operating modes, each operating mode having a predeterminednumber of steps for moving a predetermined number of slats in each groupof slats in the load-retracting direction. The multi-operating-modereciprocating slat conveyor has a means for switching between operatingmodes, the means for switching responsive to at least one operating modechanging event.

The foregoing and other objectives, features, and advantages of theinvention will be more readily understood upon consideration of thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various exemplary embodiments.

FIG. 1 is a flow chart showing an exemplary method and system of anadaptable or multi-mode reciprocating slat conveyor.

FIG. 2 is a state chart showing an exemplary simplified version of thestates of an adaptable or multi-mode reciprocating slat conveyor.

FIG. 3 is a hydraulic schematic of a preferred exemplary adaptable ormulti-mode reciprocating slat conveyor that can operate in both atwo-step non-continuous operating mode and a three-step continuousoperating mode.

FIGS. 4-8 are perspective top views from an angle, of an adaptable ormulti-mode reciprocating slat conveyor operating in a three-stepnon-continuous operating mode, that together show an exemplary unloadingprocess.

FIGS. 9-13 are perspective top views from an angle, of an adaptable ormulti-mode reciprocating slat conveyor operating in a three-stepnon-continuous operating mode, that together show an exemplary loadingprocess.

FIGS. 14-17 are perspective top views from an angle, of an adaptable ormulti-mode reciprocating slat conveyor operating in a two-stepnon-continuous operating mode, that together show an exemplary unloadingprocess.

FIGS. 18-21 are perspective top views from an angle, of an adaptable ormulti-mode reciprocating slat conveyor operating in a two-stepnon-continuous operating mode, that together show an exemplary loadingprocess.

FIG. 22 is a hydraulic schematic of an alternative preferred exemplaryadaptable or multi-mode reciprocating slat conveyor that can operate inboth a two-step non-continuous operating mode and a three-stepcontinuous operating mode.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a reciprocating slat conveyor and,more specifically, to an adaptable or multi-mode (also referred to as amulti-operating-mode) reciprocating slat conveyor.

As set forth in the Background section of this disclosure, there aremany different types of reciprocating slat conveyors. The knownreciprocating slat conveyors can be categorized based on the number of“steps” each group of slats performs in the load-retracting direction(e.g. if each slat in a three-slat group retracts individually, it is athree-step system). Exemplary reciprocating slat conveyors with two,three, four, and six steps are discussed in the Background section ofthis disclosure. The known reciprocating slat conveyors can further becategorized based on whether the slat movement is continuous ornon-continuous, and examples of both of these are discussed in theBackground section of this disclosure.

There may be advantages to each of the prior art systems regardless ofhow many steps are performed in the load-conveying direction or whetherthe slat movement is continuous or non-continuous. For example, of theknown prior art systems, two-step reciprocating slat conveyors aregenerally the quickest and most efficient (in terms of oil or poweruse). For example, less hydraulic oil is required to convey the load 30using a two-step reciprocating slat conveyor. So for the same volume ofhydraulic oil, the two-step reciprocating slat conveyor will convey at afaster rate than the three-step reciprocating slat conveyor. Two-stepreciprocating slat conveyors, however, are non-continuous and, at leastone slat in each group does not move. The problem with one slat notmoving is that there may be load material that is not removed from theload-holding compartment (poor “clean-out”). Reciprocating slatconveyors with higher numbers of steps and/or continuous movement havemore power and provide better clean-out, but are less efficient andgenerally slower. Also, different types of reciprocating slat conveyorsare particularly suitable for particular loads. For example, a two-stepreciprocating slat conveyor is particularly suited for loads that arecohesive (e.g. silage and shredded documents). Reciprocating slatconveyors having three and more steps are particularly suited for loadsthat are less cohesive (e.g. grain and fertilizer). Accordingly, all ofthe prior art systems have their strengths and weaknesses.

The adaptable or multi-mode reciprocating slat conveyor, however, isable to function in multiple step modes (e.g. both a two-step mode and athree-step mode, but could be any modes having a predetermined number ofsteps) and either in a continuous or a non-continuous mode and,therefore, has all the advantages of the various prior art reciprocatingslat conveyors. The adaptable reciprocating slat conveyor could be usedin any of the operating modes it is designed to support so that a usercould pick the best operating mode for a particular use. Further, theuser could choose an initial operating mode (characterized by having apredetermined number of steps) and then switch to a new operating mode(characterized by having a different predetermined number of steps thanthe initial operating mode). The ability to switch between operatingmodes would be particularly advantageous when the load is a “sticky”load in that there is a lot of friction with the side walls such that atfirst the load is difficult to unload. In such a situation, the initialoperating mode might be a three-step operating mode and, once the loadhas been “unstuck,” either a sensor 40 or a user could initiate a changein the operating mode to a more efficient and faster two-step operatingmode. Similarly, if a load is particularly heavy, a more powerful (morecylinders are at work) three-step operating mode may be used until theload is lighter, at which time either a sensor 40 or a user can initiatea change in the operating mode to a more efficient and faster two-stepnon-continuous operating mode.

For purposes of the adaptable reciprocating slat conveyor, an operatingmode is defined by the number of steps it uses (i.e. the predeterminednumber of steps). A characteristic of the operating mode is whether itis continuous and non-continuous. For purposes of the adaptablereciprocating slat conveyor, switching between a continuous operatingmode and a non-continuous operating mode would still be consideredswitching between operating modes. It should be noted that “on” and“off” are not considered operating modes. Further, although reversingthe direction of a reciprocating slat conveyor (e.g. switching fromloading to unloading or switching from unloading to loading) may beaccompanied by a change in operating mode, the direction itself is notconsidered in the description of the operating mode. For purposes of theadaptable reciprocating slat conveyor, switching between an “on” stateand an “off” state would not be considered switching between operatingmodes. Similarly, for purposes of the adaptable reciprocating slatconveyor, switching between a “loading” state and an “unloading” statewould not be considered switching between operating modes.

FIG. 1 is a flow chart showing an exemplary method and system related tothe adaptable reciprocating slat conveyor. This chart shows that when areciprocating slat conveyor is turned on (start) it optionally allowsthe selection of an initial operating mode 20 (alternatively, thereciprocating slat conveyor can enter into a predetermined operatingmode). If a selection of the initial operating mode is facilitated, theselection may be made by the user manually or it may be madeautomatically using one or more sensors. The reciprocating slat conveyorenters into an initial operating mode (e.g. two-step non-continuous orthree-step continuous) 22. At some point, an event (an operating modechanging event) occurs that changes the operating mode 24, and thereciprocating slat conveyor enters into a new operating mode 26. Forexample, a user can initiate the change (e.g. manual operating modechanging event), a sensor can initiate the change (e.g. sensor operatingmode changing event), the mode can change after a number of cycles (e.g.a counting mode changing event), or a timer can initiate the change(e.g. timing operating mode changing event) so that a reciprocating slatconveyor that is initially in the two-step non-continuous mode entersinto a three-step continuous mode. In another example, an operating modechanging event occurs so that a reciprocating slat conveyor that isinitially in the three-step continuous mode enters into a two-stepnon-continuous mode. Multiple operating mode changing events can occurto change the operating mode. For example, the initial operating modemight be a six-step operating mode, and events can occur such that itoperates sequentially in five-step, four-step, three-step, andeventually two-step operating modes. In yet another example, the initialoperating mode may be a two-step operating mode because it iseconomical, but a user might observe that the load is too heavy andchange it to a three-step operating mode and, thereafter, return to thetwo-step operating mode when the load is lighter. Eventually, thereciprocating slat conveyor is turned off (end), although this is nottechnically an operating mode changing event because it does not cause achange between two operating modes (“on and off” and “loading andunloading” are not technically operating modes).

FIG. 2 is a state chart showing an exemplary simplified version of thestates of an adaptable or multi-mode reciprocating slat conveyor. State28 is an operating mode change state. In this state the multi-modereciprocating slat conveyor is either waiting for instructions forchange and/or actually changing states in response to an operating modechanging event. Exemplary operating mode changing events include, butare not limited to, predetermined selection of an operating mode (e.g.an initial operating mode entered into as a result of a predeterminedmechanical configuration and/or program), user or manual selection ortriggering of an operating mode (e.g. the user selecting the operatingmode or changing to the operating mode), sensor selection or triggeringof an operating mode (e.g. a sensor triggering a change of operatingmode), timing selection or triggering of an operating mode (e.g. after apredetermined time the operating mode changes), or other selection ortriggering means of a change in operating modes. State 29 is the statein which the multi-mode reciprocating slat conveyor is actually runningin the operating mode. It should be noted that prior art (which can beconsidered to have only a single operating mode) does not have anoperating mode change state—it is either on or off and, if it is on, itis either loading or unloading. On, off, loading, and unloading are notrelevant to operating mode as defined herein.

It should be noted that FIGS. 1 and 2 are charts that illustrate methodsand systems related to the adaptable reciprocating slat conveyor. Itwill be understood that each block of these charts, and combinations ofblocks in these charts, may be implemented as part of a mechanicalsystem (e.g. in the shown hydraulic system of FIG. 3). It will also beunderstood that at least some of the blocks of these charts, parts ofthe blocks of these charts, and/or combinations of blocks in thesecharts, may be implemented by computer program instructions receivinginstructions from a user and/or sensors 40 associated with a mechanicalsystem. These computer program instructions may be loaded onto acomputer to produce a machine, such that the instructions that executeon the computer create structures for implementing the functionsspecified in the chart block or blocks. The term “loaded onto acomputer” also includes being loaded into the memory of the computer ora memory associated with or accessible by the computer. The term“memory” is meant to include any type of computer (or othertechnology)-readable medium including, but not limited to, RAM, ROM,floppy disks, hard disks, or other storage media known or yet to bediscovered. The term “computer” is meant to include any type ofprocessor, programmable logic device, or other type of programmableapparatus known or yet to be discovered. It will also be understood thateach block of the charts, and combinations of blocks in the charts, maybe divided and/or joined with other blocks of the charts withoutaffecting the scope of the invention.

The adaptable reciprocating slat conveyor operates in a plurality ofoperating modes, each operating mode having a predetermined number ofsteps for moving a predetermined number of slats in each group of slatsin said load-retracting direction. For example, an adaptablereciprocating slat conveyor can operate in two operating modes, onebeing a two-step non-continuous operating mode and one being athree-step non-continuous operating mode. A preferred exemplaryadaptable reciprocating slat conveyor is shown and described in detailwith the hydraulic schematic of FIG. 3 and the graphical representationsof the various steps of both operating modes shown in FIGS. 4-21. Itshould be noted that this is meant to be an example of an adaptable ormulti-mode reciprocating slat conveyor. Alternative adaptablereciprocating slat conveyors may have operating modes that differ fromthe two described (e.g. a two-step non-continuous operating mode and asix-step continuous operating mode), or have more than two operatingmodes (e.g. a two-step non-continuous operating mode, a three-stepnon-continuous operating mode, and a six-step non-continuous operatingmode). Still further, as can be seen from the discussion of the priorart systems, there may be multiple types of two-step non-continuousoperating modes, three-step continuous operating modes, and other knownoperating modes which differ, for example, in the sequence or speed ofslat movement. The adaptable reciprocating slat conveyor could bedesigned to work in any combination of these modes. For example, theadaptable reciprocating slat conveyor may be designed only to includetwo different types of three-step continuous operating modes or twodifferent types of three-step non-continuous operating modes.

Further, the mechanical structure of such components as the framework,slats, and seals may be as shown or may be more like those found in theprior art references discussed herein, other known prior art references,as well as known and yet to be developed mechanical structurecomponents. Similarly, the power source(s) and/or cylinders of theadaptable reciprocating slat conveyor may be like those discussed in thereferences discussed herein, other known prior art references, as wellas known and yet to be developed power source(s) and/or cylinders. Stillfurther, although the exemplary power source(s) shown and discussedherein is based on hydraulics, alternative power sources could be basedon pneumatics, electronics, or other known or yet to be developedsystems.

In the description of FIGS. 3-21, the same terms and reference numberswill be used to refer to the same or like parts. For example, hydrauliccylinders HCa, HCb, and HCc (referred to generally as hydrauliccylinders HC), cross-drives CDa, CDb, CDc (referred to generally ascross-drives CD), and floor slats FSa, FSb, FSc (referred to generallyas FS) are terms and reference numbers that are used throughout thefigures to describe similar structures. Further, for the sake ofreadability, the modifiers (a, b, and c) have been kept consistent indescribing the hydraulic cylinders HC, cross-drives CD, and floor slatsFS such that like modifiers go together (e.g. hydraulic cylinder HCa isconnected to cross-drive CDa which, in turn, is connected to floor slatsFSa. It should be noted that valves V-A, V-B, V-C, and V-D and poppetsPa1, Pa2, Pb1, Pb2, Pb3, Pc1, and Pc2 do not follow the same modifierscheme. Where otherwise not specifically defined, words, phrases,abbreviations, and/or acronyms are given their ordinary meaning in theart. It should be noted that, unless otherwise specified, the term “or”is used in its nonexclusive form (e.g. “A or B” includes A, B, A and B,or any combination thereof, but it would not have to include all ofthese possibilities). It should be noted that, unless otherwisespecified, “and/or” is used similarly (e.g. “A and/or B” includes A, B,A and B, or any combination thereof, but it would not have to includeall of these possibilities). It should be noted that, unless otherwisespecified, the term “includes” means “comprises” (e.g. a device thatincludes or comprises A and B contains A and B but optionally maycontain C or additional components other than A and B). It should benoted that, unless otherwise specified, the singular forms “a,” “an,”and “the” refer to one or more than one, unless the context clearlydictates otherwise.

As shown in FIGS. 3-21, reciprocating slat-type conveyors 10 generallyinclude a plurality of elongated floor slats FSa, FSb, FSc (alsoreferred to as “conveyor slats,” “slats,” or “deck slats” and referredto generally as FS). Conveyor systems 10 are generally used in theload-holding compartment 12 of load transport vehicles. Exemplaryload-holding compartments 12 include a mobile cargo trailer, a bed of atruck (truck bed), a rear portion of a semi-trailer, a cargo container,a container portion of a van-truck, stationary bins, or any mobile orstationary load holder. The load-holding compartments 12 have aframework that has a longitudinal direction and a transverse directionperpendicular to the longitudinal direction. Although the longitudinaldirection is generally longer than the transverse direction, these termsare not meant to be so limited. In the figures the longitudinaldirection is shown as extending from the front 14 to the rear 16. Theslats FS (also referred to as FSa, FSb, FSc) are arranged side-by-sideto form the floor of the load-holding compartment 12 so that they extendparallel to the longitudinal direction of the framework of theload-holding compartment 12. The design of the slats FS, includinglength, width, and thickness, depends upon factors including thedimensions of the floor, the construction material, and theapplication(s) for which the conveyor is to be used.

As shown in FIGS. 4-21, the slats FS are arranged in groups of slats (agroup generally includes at least three slats FSa, FSb, FSc, although itis to be understood that each group may include any desired number inexcess of two). Groups may also include one or more stationary slats.For purpose of description, respective slats from each group will bereferred to as a “set” (e.g. a set of slats would be all the FSa slats).In one exemplary operating mode, the slats FSa, FSb, FSc movesimultaneously in one direction (e.g. the “load-conveying direction”).Then the slats return in the opposite direction (e.g. the “retractiondirection”). This may be accomplished by moving one slat FSa of eachgroup (the FSa set) in the retraction direction, followed by anotherslat FSb of each group (the FSb set), and so on until all the slats (orthe majority of the slats) of each group are retracted. It should benoted that alternative adaptable reciprocating slat conveyors may usealternative slat sequences shown and described in any of the referencesthat are incorporated-by-reference herein. It should be noted that thepresent invention is not to be limited to adaptable reciprocating slatconveyors using these specific slat sequences. In principle, the floorslats FS move together, taking the load with them, and then the slats FSreturn to their starting position. In stages, with every third slat FSa,FSb, FSc (in an adaptable reciprocating slat conveyor with groups ofthree slats) moving in unison. The stationary slats (those not currentlyreturning) at least partially hold the load 30 at least partially inplace until the next cycle begins. This operation results in a step-wiseadvance (in the load-conveying direction) of a load positioned on thefloor that may be followed by partial retraction of the load on thefloor.

The shown adaptable reciprocating slat conveyor uses ahydraulically-powered conveyor system. In this shown adaptablereciprocating slat conveyor, a two-way, variable-speed, hydraulic powerunit moves the floor slats FS and allows for controlled loading,unloading, and precision metering. In the shown adaptable reciprocatingslat conveyor, the power source (power unit) includes three sub-powerunits shown as three double acting hydraulic cylinders HCa, HCb, and HCc(referred to generally as hydraulic cylinders HC). In the shownadaptable reciprocating slat conveyor, each hydraulic cylinder HCa, HCb,HCc includes a respective piston 18 a, 18 b, 18 c (each including ashaft). The size, location, and number of sub-power units (e.g.hydraulic cylinders) of the power unit(s) depend(s) on theapplication(s) of the conveyor system and the specific operating modesto be implemented. Alternative adaptable reciprocating slat conveyorsmay be powered using one or more power sources including hydraulic powersources, pneumatic power sources, electrical power sources, internalcombustion or other prime mover power sources, power sources shown anddescribed in any of the references that are incorporated-by-referenceherein, and power sources known or yet to be discovered. These powersources may also include mechanical linkage necessary to implement theadaptable reciprocating slat conveyor. Multiple sub-power units (nsub-power units) and/or multiple power sources (n power sources) may beused. It should be noted that the present invention is not to be limitedto adaptable reciprocating slat conveyors powered using these powersources and structures.

The floor slats FS are connected to the hydraulic cylinders HC byconnecting the pistons 18 a, 18 b, 18 c (or extensions of the pistons)directly or indirectly to respective lateral drive-beams or cross-drivesCDa, CDb, CDc (referred to generally as cross-drives CD) which are, inturn, connected to a plurality of floor slats FS. In preferred adaptablereciprocating slat conveyors, each hydraulic cylinder HC is connected toa respective cross-drive CD. Each movable floor slat FS is thenconnected to one cross-drive such that each movable floor slat FS in agroup is connected to a different cross-drive CD. As an example, ifthere are four slats in each group of a floor, one slat of each groupwill be attached to each cross-drive CD which will be, in turn,connected to its respective hydraulic cylinder HC. Slats attached to thesame cross-drive are considered a “set.”

In addition to floor slats, at least one power source, and cross-drives,a reciprocating slat-type conveyor 10 may include substructures such assubdecks, cross-members, and cross-drive shoes. Alternative adaptablereciprocating slat conveyors may use alternative substructure and drivemechanisms such as that shown and described in any of the referencesthat are incorporated-by-reference herein. It should be noted that thepresent invention is not to be limited to these embodiments of thesubstructure and drive mechanisms.

FIG. 3 is a hydraulic schematic of a preferred exemplary adaptablereciprocating slat conveyor that can operate in both a two-stepnon-continuous operating mode and a three-step non-continuous operatingmode. This figure shows how the three hydraulic cylinders HCa, HCb, HCcare connected to respective cross-drives CDa, CDb, CDc (which, in turn,are connected to respective floor slats FSa, FSb, FSc as shown in otherfigures). The hydraulic cylinders HCa, HCb, HCc in this figure are shownas being controlled by a series of valves and poppets.

In FIG. 3, there are six hydraulic or mechanical check valves or poppetsPa1, Pa2, Pb1, Pb2, Pb3, Pc1, and Pc2 (referred to generally as poppetsP). The poppets P monitor when the hydraulic cylinders HC reach theirrespective heads 32 and bases 34. In turn, the poppets P provide signalsto and/or control the various valves and other hydraulic cylinders HC.For example, the ends of the strokes of the front and rear movingcross-drives CD which are connected (directly or indirectly) to thepistons 18 a, 18 b, 18 c trigger poppets P which, in turn, triggervalves V (shown as four valves V-A, V-B, V-C, and V-D). The function ofpoppets is described in detail in U.S. Pat. No. 4,143,760 to Hallstrom,for example in FIGS. 3, 4, and 5 and the text describing these figures.In the adaptable reciprocating slat conveyor, the switching valve pilotis no longer controlled by direct mechanical linkage to thecross-drives, but by hydraulic linkage. Alternative adaptablereciprocating slat conveyors could incorporate the structure disclosedin U.S. Pat. No. 5,193,661 to Foster, the disclosure of which is hereinincorporated by reference.

Valve V-A, which primarily controls the flow of fluid, is shown as amain, 4-way valve. Valve V-A has two positions, shown as valve position(1) and valve position (2). In position (1), the fluid flows so that thefloor slats FS move rearward. In position (2), the fluid flows so thatthe floor slats FS move forward.

Valve V-B is shown as a pilot, 4-way valve. The primary purpose of valveV-B is to control the position of valve V-A. Valve V-B has twopositions, shown as valve position (1) and valve position (2). Thepositions are controlled by the poppets P. For example, in thethree-step mode, poppet Pa1 and poppet Pc2 are opened when a componentof the respective piston 18 a, 18 c comes in contact with the poppet andthe poppet, in turn, sends a signal to valve V-B which sends a signal toValve V-A. Similarly, in the two-step mode, poppet Pa1 and poppet Pb2are opened when a component of the respective piston 18 a, 18 c comes incontact with the poppet and the poppet, in turn, sends a signal to valveV-B which sends a signal to Valve V-A. As shown, valve V-A generally hasthe same position as valve V-B.

Valve V-C is shown as a control valve such as an on/off/forward/reverse,4-way valve. As shown, valve V-C is manually controlled (e.g. as apush-pull handle or solenoid actuated 4-way valve operated by a pushbutton operated switch) by the operator of the conveyor. Valve V-C hasthree positions, shown as valve position (1), valve position (2), andvalve position (3). In position (2), the system is in idle. As shownthere can be a detent in the neutral position that provides a solidlocation for the center position (the neutral position). In position(1), the system is unloading. In position (3), the system is loading. Itshould be noted that valve V-C may be automatically controlled by one ormore sensors 40 (shown in phantom) that senses, for example, the weightof the load 30, the height of the load 30, the position of the load 30,the motion of the load 30, the pressure of the system, or other factorswhich would warrant a change in the valve V-C position (e.g. turning thesystem on or off or changing directions). For example, the system mayoperate until the sensor 40 sensed that the load 30 is passed apredetermined position (e.g. at the rear 16), and then the sensor 40would automatically turn the system off.

Valve V-D is shown as a control valve such as a ⅔ step selector, 8-wayvalve. The primary purpose of this valve is to control whether thesystem is in the three-step operating mode or the two-step operatingmode. Valve V-D has two positions, shown as valve position (1) and valveposition (2). In position (1), the system is in the three-step operatingmode. In position (2), the system is in the two-step operating mode. Asshown, valve V-D can be manually controlled (e.g. as a push-pull handleor solenoid actuated 8-way valve operated by a push button operatedswitch) by the operator of the conveyor. It should be noted that valveV-D may be automatically controlled by one or more sensors 40 (shown inphantom) that senses, for example, the weight of the load 30, the heightof the load 30, the position of the load 30, the motion of the load 30,the pressure of the system, or other factors which would warrantswitching between operating modes. For example, the system may operatein a three-step mode until the sensor 40 sensed that the weight of theload had been reduced sufficiently so that it could be unloaded in themore power efficient two-step mode, and then the sensor 40 wouldautomatically trigger the change.

Table 1 shows a chart of the valves V and the description of thehydraulic cylinder HC motion associated with the various valve positionsof the adaptable reciprocating slat conveyor of FIG. 3.

TABLE 1 Valve Valve Valve Valve Description of Hydraulic Cylinder HCMotion V-A V-B V-C V-D S0 - Idle - Pressure line bridged to tank Any Any2 Any S1 - Three-step operating mode - Unloading - All 1 1 1 1 cylindersmove rearward S2 - Three-step operating mode - Unloading - 2 2 1 1Cylinders move forward (retract) one at a time; HCa, HCb, HCc S3 -Three-step operating mode - Loading - 1 1 3 1 Cylinders move rearward(retract) one at a time; HCc, HCb, HCa S4 - Three-step operating mode -Loading - All 2 2 3 1 cylinders move forward S5 - Two-step operatingmode - Unloading - All 1 1 1 2 cylinders move rearward (although onecylinder (HCc) may be held in this position) S6 - Two-step operatingmode - Unloading - One 2 2 1 2 cylinder (HCc) moves to (or is held in)rear position while cylinder HCa moves forward (retracts), and then HCbcylinder moves forward (retracts) S7 - Two-step operating mode -Loading - One 1 1 3 2 cylinder (HCc) moves rearward (or is held in therearmost position), then cylinder HCb moves rearward (retracts), andthen HCa cylinder moves rearward (retracts) S8 - Two-step operatingmode - Loading - One 2 2 3 2 cylinder (HCc) moves rearward (or is heldin the rearmost position), while cylinders HCa and HCb move forwardtogether

FIGS. 4-21 show an exemplary preferred adaptable reciprocating slatconveyor. This single adaptable reciprocating slat conveyor is capableof operating in an exemplary three-step non-continuous operating mode(shown unloading in FIGS. 4-8 and loading in FIGS. 9-13) and in anexemplary two-step non-continuous operating mode (shown unloading inFIGS. 14-17 and loading in FIGS. 18-21). The following paragraphs detailthe steps shown in the figures. Unless it is described as “pre-motion”,each figure depicts a motion of the preferred adaptable reciprocatingslat conveyor after the movement has taken place, with the arrowsindicating the direction in which the floor slats and cross-drives havemoved.

FIGS. 4-8 show the process of unloading in a three-step non-continuousoperating mode. As this is an unloading process, the load-conveyingdirection (motion) is from the front 14 to the back 16 of theload-holding compartment 12. In other words, the load (shown as largepackage 30 for simplicity, but more likely to be some sort ofparticulate matter) in the unloading process is moving out of theload-holding compartment 12. In this adaptable reciprocating slatconveyor, each grouping has three floor slats FSa, FSb, FSc. Forpurposes of explanation, FIG. 4 depicts a pre-motion step in which allof the floor slats FS start towards the front 14 of the load-holdingcompartment 12. FIG. 5 depicts the load conveying motion in which allthe floor slats FS have moved rearward together (toward the rear 16 inthe load-conveying direction). As this is a three-step continuousoperating mode, each of the three floor slats FSa, FSb, FSc in a groupwill be retracted individually with its respective set (toward the front14, in the load-retracting direction). FIG. 6 depicts a motion in whichfloor slats FSa (those attached to the cross-drive CDa) have beenretracted. Floor slats FSa have moved toward the front 14 of theload-holding compartment 12 in the load-retracting direction. The otherfloor slats FSb and FSc at least partially hold the load 30substantially in place during the retraction of the floor slats FSa.FIG. 7 depicts a motion in which floor slats FSb (those attached to thecross-drive CDb) have been retracted. Floor slats FSb have moved towardthe front 14 of the load-holding compartment 12 in the load-retractingdirection. The other floor slats FSa and FSc at least partially hold theload 30 substantially in place during the retraction of the floor slatsFSb. Finally, FIG. 8 depicts how floor slats FSc (those attached to thethird cross-drive CDc) have been retracted. Floor slats FSc have movedtoward the front 14 of the load-holding compartment 12 in theload-retracting direction. The other floor slats FSa and FSb at leastpartially hold the load 30 substantially in place during the retractionof the floor slats FSc. Comparing FIG. 8 with FIG. 4, it is apparentthat the load 30 has moved toward the rear 16 of the load-holdingcompartment 12. The process would be repeated until the load 30 wasremoved from the load-holding compartment 12.

Using Table 1 and FIG. 3, the load-conveying motion occurs when thesystem is in state S1 in which all the floor slats FS move to the rear16 in unison. In state S1, all the valves will be in valve position (1).Similarly, using Table 1 and FIG. 3, the load-retracting motion occurswhen the system is in state S2 in which each floor slat FS group willretract separately with their respective set. In state S2, valves V-Aand V-B will be in valve position (2) and valves V-C and V-D will be invalve position (1).

FIGS. 9-13 show the process of loading in a three-step non-continuousoperating mode. As this is a loading process, the load-conveyingdirection (motion) is from the back 16 to the front 14 of theload-holding compartment 12. In other words, the load (shown as largepackage 30 for simplicity, but more likely to be some sort ofparticulate matter) in the loading process is moving into theload-holding compartment 12. In this adaptable reciprocating slatconveyor, each grouping has three floor slats FSa, FSb, FSc. Forpurposes of explanation, FIG. 9 shows a pre-motion step in which all ofthe floor slats FS start towards the front 14 of the load-holdingcompartment 12. As this is a three-step continuous operating mode, eachof the three floor slats FSa, FSb, FSc in a group will be retractedindividually with its respective set (toward the rear 16, in theload-retracting direction). FIG. 10 depicts a motion in which floorslats FSc (those attached to the cross-drive CDc) have been retracted.Floor slats FSc have moved toward the rear 16 of the load-holdingcompartment 12 in the load-retracting direction. The other floor slatsFSa and FSb at least partially hold the load 30 substantially in placeduring the retraction of the floor slats FSc. FIG. 11 depicts a motionin which floor slats FSb (those attached to the cross-drive CDb) havebeen retracted. Floor slats FSb have moved toward the rear 16 of theload-holding compartment 12 in the load-retracting direction. The otherfloor slats FSa and FSc at least partially hold the load 30substantially in place during the retraction of the floor slats FSb.FIG. 12 depicts a motion in which floor slats FSa (those attached to thecross-drive CDa) have been retracted. Floor slats FSa have moved towardthe rear 16 of the load-holding compartment 12 in the load-retractingdirection. The other floor slats FSb and FSc at least partially hold theload 30 substantially in place during the retraction of the floor slatsFSa. FIG. 13 depicts the load conveying motion in which all the floorslats FS have moved forward together (toward the front 14 of theload-holding compartment 12 in the load-conveying direction). ComparingFIG. 13 with FIG. 9, it is apparent that the load 30 has moved towardthe front 14 of the load-holding compartment 12. The process would berepeated until the load 30 was fully loaded into the load-holdingcompartment 12.

Using Table 1 and FIG. 3, the load-retracting motion occurs when thesystem is in state S3 in which each floor slat FS set will retractseparately. In state S3, valves V-A and V-B will be in valve position(1), valve V-C will be in valve position (3), and valve V-D will be invalve position (1). Similarly, using Table 1 and FIG. 3, theload-conveying motion occurs when the system is in state S4 in which allthe floor slats FS move to the front 14 in unison. In state S4, valvesV-A and V-B will be in valve position (2) and valves V-C and V-D will bein valve position (1).

FIGS. 14-17 show the process of unloading in a two-step non-continuousoperating mode. As this is an unloading process, the load-conveyingdirection (motion) is from the front 14 to the back 16 of theload-holding compartment 12. In other words, the load (shown as largepackage 30 for simplicity, but more likely to be some sort ofparticulate matter) in the unloading process is moving out of theload-holding compartment 12. In this adaptable reciprocating slatconveyor, each grouping has three floor slats FSa, FSb, FSc, but onefloor slat FSc in each grouping does not move. For purposes ofexplanation, FIG. 14 shows a pre-motion step in which floor slat FSc hasremained stationary. FIG. 15 depicts the load conveying motion in whichfloor slats FSa and FSb have moved rearward together (toward the rear 16in the load-conveying direction) as cross-drives CDa and CDb have movedrearward. The load 30 has advanced rearward between FIG. 14 and FIG. 15.As this is a two-step non-continuous operating mode, each of the twomoving floor slats FSa and FSb in a group will be retracted individuallywith its respective set (toward the front 14, in the load-retractingdirection). FIG. 16 depicts a motion in which floor slats FSa (thoseattached to the cross-drive CDa) have been retracted. Floor slats FSahave moved toward the front 14 of the load-holding compartment 12 in theload-retracting direction. The other floor slats FSb and FSc at leastpartially hold the load 30 substantially in place during the retractionof the floor slats FSa. FIG. 17 depicts a motion in which floor slatsFSb (those attached to the cross-drive CDb) have been retracted. Floorslats FSb have moved toward the front 14 of the load-holding compartment12 in the load-retracting direction. The other floor slats FSa and FScat least partially hold the load 30 substantially in place during theretraction of the floor slats FSb. It should be noted that FIG. 17 showsthis adaptable reciprocating slat conveyor in substantially the sameposition as that shown in FIG. 14, except that the load 30 has movedtoward the rear 16 of the load-holding compartment 12. The process wouldbe repeated until the load 30 was removed from the load-holdingcompartment 12.

Using Table 1 and FIG. 3, the load-conveying motion occurs when thesystem is in state S5 in which two of the floor slats FSa and FSb moveto the rear 16 in unison. In state S5, valves V-A and V-B will be invalve position (1), valve V-C will be in valve position (1), and valveV-D will be in valve position (2). Similarly, using Table 1 and FIG. 3,the load-retracting motion occurs when the system is in state S6 inwhich two floor slats FSa and FSb from each floor slat group moveforward with their respective sets (retract) separately. In state S6,valves V-A and V-B will be in valve position (2), valve V-C will be invalve position (1), and valve V-D will be in valve position (2). In bothstate S5 and S6, valve V-D isolates hydraulic cylinder HCc from theother two cylinders HCa, HCb and, instead, the base of cylinder HCc isfed the system pressure to force it to extend completely (orsubstantially completely) and be held in the extended position while theother cylinders HCa, HCb move in the normal fashion.

In this preferred exemplary adaptable reciprocating slat conveyor, theswitch between three-step mode and two-step mode is accomplished byrerouting the flow of hydraulic oil to the hydraulic cylinders HCb andHCc. Basically this causes pressure to hold the hydraulic cylinder HCcstationary at the rearward end of its motion (so that one floor slat FScin each group is held toward the rear 16) and redirecting to hydrauliccylinder HCb the pattern of hydraulic oil flow that was controllinghydraulic cylinder HCc. It should be noted that the means for switchingto a new operating mode may include mechanical means (e.g. mechanicalswitches, mechanical valves, mechanical or electromechanical mechanismsto block HCc from moving, and other mechanical devices that allowswitching between a plurality of states), electrical means (e.g.electrical switches, electrical valves, and other electrical devicesthat allow switching between a plurality of states), processorcontrolled mechanisms (e.g. computer or processor logic units),disconnection means (e.g. mechanically, electrically, or using a signalprocessor to disconnect one or more slats per group from one or morepower sources, such as disconnecting the hydraulic cylinder HCc from thecross-drive CDc), switching mechanisms known or yet to be discovered, orcombinations of the aforementioned switching mechanisms.

FIGS. 18-21 show the process of loading in a two-step non-continuousoperating mode. As this is a loading process, the load-conveyingdirection (motion) is from the back 16 to the front 14 of theload-holding compartment 12. In other words, the load (shown as largepackage 30 for simplicity, but more likely to be some sort ofparticulate matter) in the loading process is moving into theload-holding compartment 12. In this adaptable reciprocating slatconveyor, each grouping has three floor slats FSa, FSb, FSc, but onefloor slat FSc in each grouping does not move. For purposes ofexplanation, FIG. 18 shows a pre-motion step in which floor slat FSc hasremained stationary. As this is a two-step non-continuous operatingmode, each of the two moving floor slats FSa and FSb in a group will beretracted individually with its respective set (toward the rear 16, inthe load-retracting direction). FIG. 19 depicts a motion in which floorslats FSb (those attached to the cross-drive CDb) have been retracted.The floor slats FSb have moved toward the rear 16 of the load-holdingcompartment 12 in the load-retracting direction. The other floor slatsFSa and FSc at least partially hold the load 30 substantially in placeduring the retraction of the floor slats FSb. FIG. 20 depicts a motionin which floor slats FSa (those attached to the cross-drive CDa) havebeen retracted. The floor slats FSa have moved toward the rear 16 of theload-holding compartment 12 in the load-retracting direction. The otherfloor slats FSb and FSc at least partially hold the load 30substantially in place during the retraction of the floor slats FSa.Finally, FIG. 21 depicts the load conveying motion in which floor slatsFSa and FSb have moved forward together (toward the front 14 in theload-conveying direction) as cross-drives CDa and CDb move forward. Theload 30 has advanced forward between FIG. 20 and FIG. 21. It should benoted that FIG. 21 shows this adaptable reciprocating slat conveyor insubstantially the same position as that shown in FIG. 18, except thatthe load 30 has moved toward the front 14 of the load-holdingcompartment 12. The process would be repeated until the load 30 had beenmoved into the load-holding compartment 12.

Using Table 1 and FIG. 3, the load-retracting motion occurs when thesystem is in state S7 in which two floor slats FSa and FSb from eachfloor slat group move rearward (retract) separately with theirrespective sets. In state S7, valves V-A and V-B will be in valveposition (1), valve V-C will be in valve position (3), and valve V-Dwill be in valve position (2). Similarly, using Table 1 and FIG. 3, theload-conveying motion occurs when the system is in state S8 in which twoof the floor slats FSa and FSb move to the front 14 in unison. In stateS8 Valve V-A and V-B are in position 2. In both state S7 and S8, valveV-C will be in valve position (3), and valve V-D will be in valveposition (2). In this state, valve V-D isolates hydraulic cylinder HCcfrom the other two cylinders HCa, HCb and, instead, the base of cylinderHCc is fed the system pressure to force it to extend completely (orsubstantially completely) and be held in the extended position while theother cylinders HCa, HCb move in the normal fashion.

FIG. 22 is a hydraulic schematic of an alternative preferred exemplaryadaptable or multi-mode reciprocating slat conveyor that can operate inboth a two-step non-continuous operating mode and a three-stepcontinuous operating mode. The main difference this adaptablereciprocating slat conveyor and that shown in FIG. 3 is that HCc is heldby a check valve instead of routing the input to the pressure line. Oneadvantage to this adaptable reciprocating slat conveyor is that it canuse off the shelf components and may be easier to produce. In some casesthe check valve may block HCc from moving better than the pressuremethod. When valve V-D (such as a 4-way valve, such as a DMA-G01-E3X-10produced by Nachi America, 570 “B” Telser Rd, Lake Zurich, Ill. 60047)is in position (1), PO Check 1 (a normally closed, pilot to open checkvalve such as a RP16A-01 produced by HYDAC International, 445 WindyPoint Dr, Glendale Heights, Ill. 61039) is open allowing free flow fromHCc to HCb to allow HCc to fully retract. PO Check 2 (a normally closed,pilot to open check valve such as a RP08A-01 produced by HYDACInternational, 445 Windy Point Dr, Glendale Heights, Ill. 61039) isclosed preventing the Base Pilot signal from coming from HCb Pb3 andonly allowing it to come from HCc Pc2. When valve V-D is in position(2), PO Check 1 is closed blocking HCc from retracting while allowingits extension. PO Check 2 is open allowing Base Pilot signal to comefrom HCb Pb3. Check 1 prevents oil from leaving HCc through Pc2 into thepilot signal. Like the adaptable reciprocating slat conveyor shown inFIG. 3, this adaptable reciprocating slat conveyor uses amechanically/electrically/manually operated valve V-D.

As mentioned above, alternative adaptable reciprocating slat conveyorscan be implemented using alternative structure. In addition to thosealternative adaptable reciprocating slat conveyors discussed above, theadaptable reciprocating slat conveyor may be implemented using high-techstructure. For example, poppets can be replaced with electronic ormagnetic Reed switches. Another example is that valves may be replacedwith processors and/or computers. For example, valve V-B could bereplaced with a processor, logic control unit, or a PLC computer thatreceives signals and controls valve V-A. Such technology is disclosed inU.S. Pat. No. 5,839,568 to Clark, which is incorporated herein byreference. Further, alternative adaptable reciprocating slat conveyorscould be implemented that provide the user with two different operatingmodes (e.g. a three-step non-continuous operating mode and a four-stepcontinuous operating mode) or more than two operating modes. Theoperating modes may be known operating modes (e.g. those discussed inthe patent references disclosed herein) or operating modes yet to bedeveloped. Still further, the floor slat arrangement may be similar tothat described in U.S. Pat. No. 4,856,645 to Hallstrom (the disclosureof which is herein incorporated by reference) that shows the stationarythird slat between each moving slat as well as the stationary slat beingnarrower than the moving slats.

It should be noted that the use of numbers and letters is primarily forpurposes of identification and not necessarily as an indication oforder.

It should be noted that all publications, patents, and patentapplications cited herein, whether supra or infra, are herebyincorporated by reference in their entirety.

The terms and expressions that have been employed in the foregoingspecification are used as terms of description and not of limitation,and are not intended to exclude equivalents of the features shown anddescribed. This application is intended to cover any adaptations orvariations of the present invention. It will be appreciated by those ofordinary skill in the art that any arrangement that is calculated toachieve the same purpose may be substituted for the specific embodimentshown. It is also to be understood that the following claims areintended to cover all of the generic and specific features of theinvention herein described and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

1. A multi-operating-mode reciprocating slat conveyor, comprising: (a) aplurality of slats arranged in groups, said slats movable in aload-conveying direction and a load-retracting direction; (b) at leastone power source, one slat of each group attached to said at least onepower source; (c) a plurality of operating modes, each operating modehaving a predetermined number of steps for moving a predetermined numberof slats in each group of slats in said load-retracting direction; (d)at least one of said plurality of operating modes being an initialoperating mode; and (e) means for switching to a new operating mode,said means for switching responsive to at least one operating modechanging event.
 2. The multi-operating-mode reciprocating slat conveyorof claim 1, said at least one power source including a plurality ofsub-power units, one slat of each group attached to one of saidplurality of sub-power units.
 3. The multi-operating-mode reciprocatingslat conveyor of claim 1, each said operating mode being continuous ornon-continuous.
 4. The multi-operating-mode reciprocating slat conveyorof claim 1, wherein said initial operating mode is user selectable. 5.The multi-operating-mode reciprocating slat conveyor of claim 1, whereinsaid initial operating mode is determined by at least one sensor.
 6. Themulti-operating-mode reciprocating slat conveyor of claim 1, whereinsaid means for switching is repeatedly responsive to operating modechanging events.
 7. The multi-operating-mode reciprocating slat conveyorof claim 1, wherein at least one operating mode uses a predeterminednumber of steps equal to the number of slats in each group for movingsaid slats in each group in said load-retracting direction.
 8. Themulti-operating-mode reciprocating slat conveyor of claim 1, wherein atleast one operating mode uses a predetermined number of steps equal toone less than the number of slats in each group for moving said slats ineach group in said load-retracting direction, one of said slats in eachgroup remaining stationary.
 9. The multi-operating-mode reciprocatingslat conveyor of claim 1, wherein said initial operating mode has adifferent predetermined number of steps than said new operating mode.10. The multi-operating-mode reciprocating slat conveyor of claim 1,wherein said means for switching to a new operating mode is selectedfrom the group consisting of: (a) mechanical switches; (b) electricalswitches; (c) mechanical valves; (d) electrical valves; (e) computer orprocessor logic units; (f) mechanical mechanisms; (g) disconnectionmeans; and (h) combinations of the means for switching set forth in(a)-(g).
 11. The multi-operating-mode reciprocating slat conveyor ofclaim 1, wherein said at least one operating mode changing event isselected from the group consisting of: (a) a predetermined selection ofan operating mode; (b) a manual operating mode changing event; (b) asensor operating mode changing event; (c) a timing operating modechanging event; (d) a counting mode changing event (number of cycles);and (e) a combination of (a)-(e).
 12. A multi-operating-modereciprocating slat conveyor for loading and unloading at least one loadfrom a load-holding compartment, comprising: (a) a plurality of slatsarranged in groups of n slats, said slats movable in a load-conveyingdirection and a load-retracting direction, wherein n is a number greaterthan or equal to three (3); (b) n power sources, one slat of each groupattached to each power source; (c) a plurality of operating modes, eachoperating mode having a predetermined number of steps for moving apredetermined number of slats in each group of slats in saidload-retracting direction; and (d) means for switching between operatingmodes, said means for switching responsive to at least one operatingmode changing event.
 13. The multi-operating-mode reciprocating slatconveyor of claim 12, said n power sources being n sub-power units of asingle power unit.
 14. The multi-operating-mode reciprocating slatconveyor of claim 12, each said operating mode being continuous ornon-continuous.
 15. The multi-operating-mode reciprocating slat conveyorof claim 12, said at least one operating mode changing event is selectedfrom the group consisting of: (a) a predetermined selection of anoperating mode; (b) a manual operating mode changing event; (b) a sensoroperating mode changing event; (c) a timing operating mode changingevent; (d) a counting mode changing event (number of cycles); and (e) acombination of (a)-(e).
 16. The multi-operating-mode reciprocating slatconveyor of claim 12, wherein said means for switching is repeatedlyresponsive to operating mode changing events.
 17. Themulti-operating-mode reciprocating slat conveyor of claim 12, wherein atleast one operating mode uses n steps for moving said slats in saidload-retracting direction.
 18. The multi-operating-mode reciprocatingslat conveyor of claim 12, wherein at least one operating mode uses n−1steps for moving said slats in said load-retracting direction, one ofsaid slats in each group remaining stationary.
 19. Themulti-operating-mode reciprocating slat conveyor of claim 12, whereinsaid means for switching to a new operating mode is selected from thegroup consisting of: (a) mechanical switches; (b) electrical switches;(c) mechanical valves; (d) electrical valves; (e) computer or processorlogic units; (f) mechanical mechanisms; and (g) combinations of themeans for switching set forth in (a)-(f).
 20. A multi-operating-modereciprocating slat conveyor, comprising: (a) a plurality of slatsarranged in groups, said slats movable in a load-conveying direction anda load-retracting direction; (b) at least one power source, one slat ofeach group attached to said at least one power source; (c) at least twooperating modes, each operating mode having a predetermined number ofsteps for moving a predetermined number of slats in each group of slatsin said load-retracting direction; (i) a first operating mode using apredetermined number of steps equal to the number of slats in each groupfor moving said slats in each group in said load-retracting direction;and (ii) a second operating mode using a predetermined number of stepsequal to one less than the number of slats in each group for moving saidslats in each group in said load-retracting direction; (d) at least oneof said plurality of operating modes being an initial operating mode;and (e) means for switching to a new operating mode, said means forswitching responsive to at least one operating mode changing event.